How to check whether sfp/optical module is damaged?

Here are the steps to troubleshoot:
a)  Check whether the optical fiber transceiver is inserted reversely
Pull out the optical fiber, switch the transceiver end of the optical fiber, insert it again, and check whether the indicator light of the optical port is on.
b) Check whether the fiber model matches
According to the model of the optical module, check whether the wavelength and rate of the optical modules at both ends are the same.
c)   Check the media of the optical multiplexing port
1) Here is the command to check it: show interface + port number
2) If the medium type is wrong, use medium-type fiber to switch to optical port
Ruijie#config t
Enter configuration commands, one per line.  End with CNTL/Z.
Ruijie(config)#int gi 0/2
Ruijie(config-GigabitEthernet0/2)#medium-type fiber
Note:

For an aggregated interface, if you want to change the media type, you may need to launch the link aggregation mode first, and then modify the media type.
d) Check rate duplex configuration
It is generally recommended to use the default auto-negotiation rate duplex, but adjustments are required in the following cases:
1)The peer device does not support auto-negotiation, such as optoelectronic transceivers, you need to specify the rate duplex and flow control on the switch on our end
2)The speed of the installed optical module is inconsistent with the interface speed. For example, if a Mini-GBIC Gigabitoptical module is inserted into an SFP interface that supports 10 Gigabit speed, the speed needs to be specified.
3) The peer device is configured with forced rate and duplex, then our end needs to be configured the same
Here are commands need to configure:
Ruijie#showrun int te 1/2
Ruijie(config)#intte 1/2
Ruijie(config-TenGigabitEthernet 1/2)#speed10g  //
Specify the interface rate
Ruijie(config-TenGigabitEthernet 1/2)#duplex full  //
Specifyfull duplex
Ruijie(config-TenGigabitEthernet1/2)#flowcontrol off     // turn off flow control
Ruijie(config-TenGigabitEthernet1/2)#end
Ruijie#showrun int te 1/2
e) Check optical transceiver power (check optical attenuation)
Check the transmit/receive power value on the optical module. If the RX Power is less than the minimum receive light intensity of the module, Link UP cannot be performed. Please perform the following troubleshooting:
1) Check the correspondence between optical modules and fiber wavelengths
2) Replacing pigtails
3) Check whether the total length of the optical fiber exceeds the maximum distance supported by the optical module, or use a tester to test whether the optical attenuation of the optical fiber is too large.
Note:

Checking the received and received light intensity of an optical module requires the hardware and software support ofthe optical module and switch. If the command prompts Unknown Command, you need to use an external optical power meter to check.
Here is the command to check the transceiver power:
Ruijie#show int te 1/1 transceiver
Here is the example when the received light intensity is too weak：
Ruijie#show int te 3/1 transceiver diagnosis      
Current diagnostic parameters :
Temp(Celsius)   Voltage(V)      Bias(mA)        RX power(dBm)   TX power(dBm)
34(OK)          4.99(OK)        5.88(OK)        -28.24(alarm)  -2.78(OK)
f) Single-port transceiver self-loop test
Use a single-core fiber to short-circuit the transceiver ends of the optical module to check whether it is Link up.
If Link UP is possible, it means that the local switch and optical module are working normally. Please check the switch configuration and optical transceiver power.
If the Linkup fails, the switch port or optical module is damaged. Please replace it one by one.
If the interface light is on, it means that there is no problem with the port and optical module.




g) Substitution method to test
1)   Change the switch port
2)   Replace the optical module
3)   Replace the switch